Did Kirstie Alley Lose the Battle of the Bulge?

Losing weight isn't easy, even for celebrities who might have perks that the average dieter doesn't, such as personal trainers to kick them into shape at the gym or private chefs to ensure all their meals are low in fat and calories.

For some stars, even that's not enough.

Actress Kirstie Alley's yo-yoing weight has kept her plastered on the covers of tabloid and gossip magazines for years, enough so that she turned weight fluctuation into a money-maker. Alley starred in a 2005 reality show called "Fat Actress" and later landed a spot as a spokesperson for Jenny Craig, one of the nation's most popular diet programs.

In 2006 she even pranced around in a bikini on the stage of Oprah Winfrey's talk show, showing off her slimmed-down physique after shedding pounds on the Jenny Craig program.

Recent headlines announcing that Jenny Craig had dropped Alley, who was once synonymous with the company, from its ad campaign were followed by reports that she has plans to launch her own weight-loss program.

But while weight loss will apparently continue to be lucrative for Alley, some nutritionists say her departure from Jenny Craig, which many consider a "fad diet," could provoke others to abandon the program as well.

Weight Struggles Continue

Alley's continued battle with the bulge was rumored to be the reason the actress was let go from Jenny Craig, where she had been the brand's celebrity face since 2005, but neither the weight-loss company nor Alley's publicist would comment directly on Alley's departure.

In a statement Jenny Craig provided to ABCNEWS.com, the company said, "After being a celebrity client for our program these past three years — losing 75 lbs. and maintaining that weight loss for over a year — Kirstie Alley is ready to move on to other creative challenges."

In addition to announcing Alley's departure, the company introduced two new celebrity spokeswomen — actresses Queen Latifah and Valerie Bertinelli.

Calls and e-mails to Alley's publicist were not immediately returned, but the actress has plans to launch her own diet program in 2009, according to The Associated Press.

Nutritionists and diet experts told ABCNEWS.com that the presumed negative experience Alley had with what they consider to be a popular "fad diet" may do wonders for other dieters, perhaps discouraging them from buying into gimmicky weight loss plans.

"If we had a little less enthusiasm about quick fix diet magic and more commitment to eating better and being more active, the public health would benefit enormously," said Dr. David Katz, a nutrition expert at Yale University in New Haven, Conn. "Maybe Kirstie Alley will have that effect, maybe it will slowly sink through to people that these quick fix diets are not the answer."

If A Celeb Can't Do It, Can I?

Katz said the departure of a well-known spokesperson like Alley could have one of several effects on dieters who have rallied around her and Jenny Craig.

"It may be that for some, when they watch high-profile people — even with their money and support — go through the same struggle with weight loss, it's a little bit easier to accept their own struggles," said Katz. "And hopefully people will forgive themselves for that struggle."

While Alley may convince other dieters that fad diets don't work, said Katz, the worst thing that could happen is for dieters to give up altogether on their weight loss goals and adopt an attitude of "if she can't do it, neither can I."

Jim Foster, the editor of Diet-Blog.com, told ABCNEWS.com that the failure of a weight loss program's spokesperson is definitely a sign to fellow dieters that perhaps that plan isn't going to work, but added that the spokesperson for a brand is often not someone many people can identify with.

"Right or wrongly, many of us view celebrities as 'privileged' — the ones that can afford personal trainers and home-delivered meals," said Foster. "Because of this, we have a perception that psychical transformation must be easier for them."

"With that said, I'm not sure how many people honestly identify with a celebrity figure. We tend to put them in the 'unreal' category — a source of entertainment rather than inspiration," said Foster.

Carla Wolper, a nutritionist at the Obesity Research Center at St. Luke Hospital in New York, said she doubts the loss of a spokesperson will have much of an effect on anyone.

"Even if someone flunks at a diet, if they're doing well then they're not going to suddenly just quit," said Wolper. "If most people find a method that is successful and they're not having any trouble adhering to the method, it won't matter if the CEO and the spokesperson [leaves the company]."

Bad Dieter? Bad for Business

While dieters like Foster may not care very much about the spokesperson for a particular diet, nutritionists say companies put a great deal of thought into who they have representing their weight loss programs.

"Sometimes people really do care about the spokespeople [of a diet plan]," said Debbie Then, a clinical psychologist who specializes in women's appearance issues. "If they don't like the person to begin with, they may not pay attention to the diet."

"Companies pay a lot of attention to who they name a spokesperson," added Then, who said that her chief complaint with many diets is the lack of acknowledgement of some of the underlying reasons people over-eat and become obese, such as emotional problems.

"Dieters like role models and people who they emulate," said Then. "Initially companies pick people who a wide variety of people can identify with, and I do think it's hard to all of a sudden have that person gone."

There has never been a scientific study that compares the success of programs like Jenny Craig with and without a recognizable spokesperson, but Yale's Katz said spokespeople are undoubtedly a large investment for companies.

"We know that big companies with deep pockets routinely use celebrities to endorse," said Katz. "Clearly the value of a celebrity to represent your product is well established."

"But if you have a high-profile spokesperson on your diet plan and they're gaining weight, that's not good for business."